Multi-view learning (MVL) is an emerging field in machine learning that focuses on improving generalization performance by leveraging complementary information from multiple perspectives or views. Various multi-view support vector machine (MvSVM) approaches have been developed, demonstrating significant success. Moreover, these models face challenges in effectively capturing decision boundaries in high-dimensional spaces using the kernel trick. They are also prone to errors and struggle with view inconsistencies, which are common in multi-view datasets. In this work, we introduce the multiview twin restricted kernel machine (TMvRKM), a novel model that integrates the strengths of kernel machines with the multiview framework, addressing key computational and generalization challenges associated with traditional kernel-based approaches. Unlike traditional methods that rely on solving large quadratic programming problems (QPPs), the proposed TMvRKM efficiently determines an optimal separating hyperplane through a regularized least squares approach, enhancing both computational efficiency and classification performance. The primal objective of TMvRKM includes a coupling term designed to balance errors across multiple views effectively. By integrating early and late fusion strategies, TMvRKM leverages the collective information from all views during training while remaining flexible to variations specific to individual views. The proposed TMvRKM model is rigorously tested on UCI, KEEL, and AwA benchmark datasets. Both experimental results and statistical analyses consistently highlight its exceptional generalization performance, outperforming baseline models in every scenario. The source code of the proposed TMvRKM model is available at https://github.com/mtanveer1/TMvRKM.

Recent advancements in neural networks, supported by foundational theoretical insights, emphasize the superior representational power of complex numbers. However, their adoption in randomized neural networks (RNNs) has been limited due to the lack of effective methods for transforming real-valued tabular datasets into complex-valued representations. To address this limitation, we propose two methods for generating complex-valued representations from real-valued datasets: a natural transformation and an autoencoder-driven method. Building on these mechanisms, we propose RVFL-X, a complex-valued extension of the random vector functional link (RVFL) network. RVFL-X integrates complex transformations into real-valued datasets while maintaining the simplicity and efficiency of the original RVFL architecture. By leveraging complex components such as input, weights, and activation functions, RVFL-X processes complex representations and produces real-valued outputs. Comprehensive evaluations on 80 real-valued UCI datasets demonstrate that RVFL-X consistently outperforms both the original RVFL and state-of-the-art (SOTA) RNN variants, showcasing its robustness and effectiveness across diverse application domains.

One of the major difficulties in machine learning methods is categorizing datasets that are imbalanced. This problem may lead to biased models, where the training process is dominated by the majority class, resulting in inadequate representation of the minority class. Universum twin support vector machine (UTSVM) produces a biased model towards the majority class, as a result, its performance on the minority class is often poor as it might be mistakenly classified as noise. Moreover, UTSVM is not proficient in handling datasets that contain outliers and noises. Inspired by the concept of incorporating prior information about the data and employing an intuitionistic fuzzy membership scheme, we propose intuitionistic fuzzy universum twin support vector machines for imbalanced data (IFUTSVM-ID) by enhancing overall robustness. We use an intuitionistic fuzzy membership scheme to mitigate the impact of noise and outliers. Moreover, to tackle the problem of imbalanced class distribution, data oversampling and undersampling methods are utilized. Prior knowledge about the data is provided by universum data. This leads to better generalization performance. UTSVM is susceptible to overfitting risks due to the omission of the structural risk minimization (SRM) principle in their primal formulations. However, the proposed IFUTSVM-ID model incorporates the SRM principle through the incorporation of regularization terms, effectively addressing the issue of overfitting. We conduct a comprehensive evaluation of the proposed IFUTSVM-ID model on benchmark datasets from KEEL and compare it with existing baseline models. Furthermore, to assess the effectiveness of the proposed IFUTSVM-ID model in diagnosing Alzheimer’s disease (AD), we applied them to the Alzheimer’s Disease Neuroimaging Initiative (ADNI) dataset. Experimental results showcase the superiority of the proposed IFUTSVM-ID models compared to the baseline models. The supplementary material of the paper can be accessed using the following link: https://github.com/mtanveer1/IFUTSVM-ID.

Alzheimer's disease (AD) and Schizophrenia (SCZ) are prominent neurodegenerative conditions and leading causes of dementia, resulting in progressive cognitive decline and memory loss. Several studies reveal that early detection and intervention can slow the progression of AD and SCZ. Numerous machine learning algorithms including twin support vector machine (TSVM) have been proposed for the early diagnosis of AD and SCZ. However, TSVM grapples with significant challenges: 1) TSVM relies on the hinge loss function, resulting in susceptibility to noise and instability; 2) TSVM encounters challenges in effectively handling large datasets, attributed to its computational complexity and dependence on matrix inversions. Keeping in view the aforementioned challenges, in this article, we propose a novel granular ball twin support vector machine with pinball loss function (Pin-GBTSVM). Pin-GBTSVM employs granular balls, as opposed to individual data points, as inputs for constructing a classifier, while also leveraging the pinball loss function to attain a heightened level of noise insensitivity. The proposed Pin-GBTSVM persists in facing challenges associated with the absence of integration of the structural risk minimization (SRM) principle and the requirement for matrix inversions. We further propose a novel large-scale Pin-GBTSVM (Pin-LGBTSVM). Pin-LGBTSVM achieves two crucial objectives: 1) it eliminates the necessity for matrix inversions, streamlining the computational efficiency of Pin-GBTSVM; and 2) it integrates the SRM principle by incorporating regularization terms, effectively addressing the concern of overfitting. Experiments are conducted on University of California Irvine (UCI), knowledge extraction based on evolutionary learning (KEEL), and normally distributed clustered (NDC) benchmark datasets, where both the proposed Pin-GBTSVM and Pin-LGBTSVM models consistently outperform the baseline models in terms of generalization performance. Furthermore, we implemented the proposed Pin-GBTSVM and Pin-LGBTSVM models on SCZ and Alzheimer's Disease Neuroimaging Initiative (ADNI) datasets, showcasing the model's efficacy in real-world applications.

Twin support vector machine (TSVM) is an emerging machine learning model with versatile applicability in classification and regression endeavors. Nevertheless, TSVM confronts noteworthy challenges: 1) the imperative demand for matrix inversions presents formidable obstacles to its efficiency and applicability on large-scale datasets; 2) the omission of the structural risk minimization (SRM) principle in its primal formulation heightens the vulnerability to overfitting risks; and 3) the TSVM exhibits a high susceptibility to noise and outliers and also demonstrates instability when subjected to resampling. In view of the aforementioned challenges, we propose the granular ball TSVM (GBTSVM). GBTSVM takes granular balls (GBs), rather than individual data points, as inputs to construct a classifier. These GBs, characterized by their coarser granularity, exhibit robustness to resampling and reduced susceptibility to the impact of noise and outliers. We further propose a novel large-scale GBTSVM (LS-GBTSVM). LS-GBTSVM's optimization formulation ensures two critical facets: 1) it eliminates the need for matrix inversions, streamlining the LS-GBTSVM's computational efficiency; and 2) it incorporates the SRM principle through the incorporation of regularization terms, effectively addressing the issue of overfitting. The proposed LS-GBTSVM exemplifies efficiency, scalability for large datasets, and robustness against noise and outliers. We conduct a comprehensive evaluation of the GBTSVM and LS-GBTSVM models on benchmark datasets from UCI and KEEL, both with and without the addition of label noise, and compared with existing baseline models. Furthermore, we extend our assessment to the large-scale NDC datasets to establish the practicality of the proposed models in such contexts. Our experimental findings and rigorous statistical analyses affirm the superior generalization prowess of the proposed GBTSVM and LS-GBTSVM models compared to the baseline models. The source code of the proposed GBTSVM and LS-GBTSVM models are available at https://github.com/mtanveer1/GBTSVM.

Alzheimer's disease (AD) is the leading neurodegenerative disorder and primary cause of dementia. Researchers are increasingly drawn to automated diagnosis of AD using neuroimaging analyses. Conventional deep learning (DL) models excel in constructing learning classifiers in early-stage AD diagnosis. However, they often struggle with AD diagnosis due to uncertainties stemming from unclear annotations by experts, challenges in data collection, such as data harmonization issues, and limitations in equipment resolution. These factors contribute to imprecise data, hindering accurate analysis, interpretation of obtained results, and understanding of complex symptoms. In response, the integration of fuzzy logic into DL, forming fuzzy deep learning (FDL), effectively manages imprecise data and provides interpretable insights, offering a valuable advancement in AD. Therefore, exploring recent advancements in integrating DL with fuzzy logic is crucial for improving AD diagnosis. In this review, we explore the contributions of fuzzy logic within FDL models, focusing on fuzzy-based image preprocessing, segmentation, and classification. Moreover, in exploring research directions, we discuss the possibility of the fusion of multimodal data with fuzzy logic, addressing challenges in AD diagnosis. Leveraging fuzzy logic and membership while integrating diverse datasets, such as genomics, proteomics, and metabolomics may provide an effective development of a DL classifier. In addition, fuzzy explainable DL promises more accurate and linguistically interpretable decision support systems for AD diagnosis. The primary objective of this article is to serve as a comprehensive and authoritative resource for newcomers, researchers, and clinicians interested in employing FDL models for AD diagnosis.